Hard fork tryout: better PoW encapsulation in block header (mimblewim…

…ble#1478)

* Improve encapsulation with ProofOfWork struct
* Add dual pow scaling factor, fix test
* Fix pre_pow serialization, chain tests
* Adjust header serialized size calc
* Hard fork handling, version-based serialization

api/src/types.rs

@@ -521,10 +521,10 @@ impl BlockHeaderPrintable {
 			output_root: util::to_hex(h.output_root.to_vec()),
 			range_proof_root: util::to_hex(h.range_proof_root.to_vec()),
 			kernel_root: util::to_hex(h.kernel_root.to_vec()),
-			nonce: h.nonce,
-			cuckoo_size: h.pow.cuckoo_sizeshift,
-			cuckoo_solution: h.pow.nonces.clone(),
-			total_difficulty: h.total_difficulty.to_num(),
+			nonce: h.pow.nonce,
+			cuckoo_size: h.pow.cuckoo_sizeshift(),
+			cuckoo_solution: h.pow.proof.nonces.clone(),
+			total_difficulty: h.pow.total_difficulty.to_num(),
 			total_kernel_offset: h.total_kernel_offset.to_hex(),
 		}
 	}

chain/src/pipe.rs

@@ -392,14 +392,14 @@ fn validate_header(header: &BlockHeader, ctx: &mut BlockContext) -> Result<(), E
 	}
 
 	if !ctx.opts.contains(Options::SKIP_POW) {
-		if global::min_sizeshift() > header.pow.cuckoo_sizeshift {
+		if global::min_sizeshift() > header.pow.cuckoo_sizeshift() {
 			return Err(ErrorKind::LowSizeshift.into());
 		}
-		if !(ctx.pow_verifier)(header, header.pow.cuckoo_sizeshift) {
+		if !(ctx.pow_verifier)(header, header.pow.cuckoo_sizeshift()) {
 			error!(
 				LOGGER,
 				"pipe: validate_header failed for cuckoo shift size {}",
-				header.pow.cuckoo_sizeshift,
+				header.pow.cuckoo_sizeshift()
 			);
 			return Err(ErrorKind::InvalidPow.into());
 		}
@@ -436,11 +436,11 @@ fn validate_header(header: &BlockHeader, ctx: &mut BlockContext) -> Result<(), E
 	// check the pow hash shows a difficulty at least as large
 	// as the target difficulty
 	if !ctx.opts.contains(Options::SKIP_POW) {
-		if header.total_difficulty.clone() <= prev.total_difficulty.clone() {
+		if header.total_difficulty() <= prev.total_difficulty() {
 			return Err(ErrorKind::DifficultyTooLow.into());
 		}
 
-		let target_difficulty = header.total_difficulty.clone() - prev.total_difficulty.clone();
+		let target_difficulty = header.total_difficulty() - prev.total_difficulty();
 
 		if header.pow.to_difficulty() < target_difficulty {
 			return Err(ErrorKind::DifficultyTooLow.into());

chain/src/store.rs

@@ -446,8 +446,8 @@ impl Iterator for DifficultyIter {
 			let prev_difficulty = self
 				.prev_header
 				.clone()
-				.map_or(Difficulty::zero(), |x| x.total_difficulty);
-			let difficulty = header.total_difficulty - prev_difficulty;
+				.map_or(Difficulty::zero(), |x| x.total_difficulty());
+			let difficulty = header.total_difficulty() - prev_difficulty;
 
 			Some(Ok((header.timestamp.timestamp() as u64, difficulty)))
 		} else {

chain/src/types.rs

@@ -78,7 +78,7 @@ impl Tip {
 			height: bh.height,
 			last_block_h: bh.hash(),
 			prev_block_h: bh.previous,
-			total_difficulty: bh.total_difficulty.clone(),
+			total_difficulty: bh.total_difficulty(),
 		}
 	}
 }

chain/tests/data_file_integrity.rs

@@ -169,6 +169,6 @@ fn _prepare_block_nosum(
 		Ok(b) => b,
 	};
 	b.header.timestamp = prev.timestamp + Duration::seconds(60);
-	b.header.total_difficulty = Difficulty::from_num(diff);
+	b.header.pow.total_difficulty = Difficulty::from_num(diff);
 	b
 }

chain/tests/mine_simple_chain.rs

@@ -77,9 +77,9 @@ fn mine_empty_chain() {
 		} else {
 			global::min_sizeshift()
 		};
-		b.header.pow.cuckoo_sizeshift = sizeshift;
+		b.header.pow.proof.cuckoo_sizeshift = sizeshift;
 		pow::pow_size(&mut b.header, difficulty, global::proofsize(), sizeshift).unwrap();
-		b.header.pow.cuckoo_sizeshift = sizeshift;
+		b.header.pow.proof.cuckoo_sizeshift = sizeshift;
 
 		let bhash = b.hash();
 		chain.process_block(b, chain::Options::MINE).unwrap();
@@ -390,9 +390,9 @@ fn output_header_mappings() {
 		} else {
 			global::min_sizeshift()
 		};
-		b.header.pow.cuckoo_sizeshift = sizeshift;
+		b.header.pow.proof.cuckoo_sizeshift = sizeshift;
 		pow::pow_size(&mut b.header, difficulty, global::proofsize(), sizeshift).unwrap();
-		b.header.pow.cuckoo_sizeshift = sizeshift;
+		b.header.pow.proof.cuckoo_sizeshift = sizeshift;
 
 		chain.process_block(b, chain::Options::MINE).unwrap();
 
@@ -479,8 +479,8 @@ where
 		Ok(b) => b,
 	};
 	b.header.timestamp = prev.timestamp + Duration::seconds(60);
-	b.header.total_difficulty = prev.total_difficulty.clone() + Difficulty::from_num(diff);
-	b.header.pow = core::core::Proof::random(proof_size);
+	b.header.pow.total_difficulty = prev.total_difficulty() + Difficulty::from_num(diff);
+	b.header.pow.proof = core::core::Proof::random(proof_size);
 	b
 }
 

core/src/consensus.rs

@@ -105,16 +105,16 @@ pub const HARD_FORK_INTERVAL: u64 = 250_000;
 /// 6 months interval scheduled hard forks for the first 2 years.
 pub fn valid_header_version(height: u64, version: u16) -> bool {
 	// uncomment below as we go from hard fork to hard fork
-	if height <= HARD_FORK_INTERVAL && version == 1 {
-		true
-	/* } else if height <= 2 * HARD_FORK_INTERVAL && version == 2 {
-		true */
-	/* } else if height <= 3 * HARD_FORK_INTERVAL && version == 3 {
-		true */
-	/* } else if height <= 4 * HARD_FORK_INTERVAL && version == 4 {
-		true */
-	/* } else if height > 4 * HARD_FORK_INTERVAL && version > 4 {
-		true */
+	if height < HEADER_V2_HARD_FORK {
+		version == 1
+	} else if height < HARD_FORK_INTERVAL {
+		version == 2
+	} else if height < 2 * HARD_FORK_INTERVAL {
+		version == 3
+	/* } else if height < 3 * HARD_FORK_INTERVAL {
+		version == 4 */
+	/* } else if height >= 4 * HARD_FORK_INTERVAL {
+		version > 4 */
 	} else {
 		false
 	}
@@ -249,3 +249,5 @@ pub trait VerifySortOrder<T> {
 	/// Verify a collection of items is sorted as required.
 	fn verify_sort_order(&self) -> Result<(), Error>;
 }
+
+pub const HEADER_V2_HARD_FORK: u64 = 95_000;